The present invention relates to disposable capsules for prepackaging, storing and eventually mixing mercury and silver powder to form a dental amalgam.
Disposable capsules useful to maintain coreactive components such as dental amalgam precursors of mercury and silver or silver alloy are well-known. In all of the prior art disposable capsules, however, some manipulation of the capsule is required to effect mixing the coreactive components.
It would be very desirable to eliminate any such manipulation of the capsule and especially in the dental art it would be desirable to have a dental capsule containing the dental amalgam precursors from which a dental amalgam could be prepared merely by placing such capsule into an amalgamator.
Examples of prior art of disposable capsules include capsules having rupturable membranes and means for rupturing said membranes prior to mixing of coreactive components. For example, U.S. Pat. No. 3,451,540 teaches a disposable capsule comprising a telescoping cylinder which is activated by sliding the separate section together to rupture the membrane which divides the capsule into two chambers and thereby allows the coreactants maintained separate in such chambers to mix. Similar capsules are disclosed in U.S. Pat. Nos. 3,625,349 and 3,595,439 wherein the membrane is in the form of a pouch, containing a coreactant and such pouch is ruptured by either squeezing through a rotating mechanism or a sliding mechanism until it bursts. See also U.S. Pat. Nos. 3,907,106; 3,860,114; 3,841,467; 3,831,742, 3,655,035; 3,638,918; 3,756,571; and 1,774,258 for similar capsules.
Disposable capsules which utilize a removable plug to isolate the coreactive components and which plug is removed to allow such components to mix are also known in the art. See for example, U.S. Pat. No. 3,275,302, wherein a ball or a disk is positioned to divide the capsule into two chambers each containing a coreactive component. This capsule is activated by turning the capsule upside down to dislodge the ball or disk. See also U.S. Pat. Nos. 3,796,303; 3,809,225; 2,527,992; 2,527,991; and 3,785,481 for other capsules utilizing removable plugs.
Other disposable capsules employ a passageway between the two chambers which can be closed and opened by either twisting, sliding or unscrewing one or more sections of the capsule. For example, in U.S. Pat. No. 3,357,545 the top of the capsule is unscrewed to remove a stem on the upper section of said capsule from a conduit in the lower section. Removal of such stem allows the coreactive component maintained in the upper section to fall into the lower section. Also see U.S. Pat. Nos. 3,139,180; 3,139,181; 3,917,062; 3,963,120; and 3,924,741 for similar capsules.
It is accordingly an object of the present invention to provide a capsule for prepackaging and storing the precursors of dental amalgam, particularly mercury and silver or silver alloy. It is a further object of this invention to provide a dental capsule which allows the precursors to be mixed and the amalgam formed with no special manipulation of the dental capsule on the part of the user. It is yet a further object of this invention to provide a dental capsule which minimizes the possibility of mercury escaping into the environment either before or during the formation of the dental amalgam. These and other objects of the present invention will be apparent from the ensuing description and claims.